Numerous call processing features such as, for instance, consultation, toggle, transfer, etc. that are controlled by network nodes or switching equipment involved in a respective connection are available in modern telephone networks for connected terminals. Telephone networks of said type are frequently composed in a heterogeneous manner of subnetworks and/or network sections that differ with respect to the types of trunk circuits they employ. To cite instances, for example analog telephone lines, ISDN-based TDM lines (TDM: Time Division Multiplexing), or internet-protocol-based LAN or WAN connections (LAN: Local Area Network; WAN: Wide Area Network) can be provided as trunk circuits.
As well as for voice communication, a communication network of said type can as a rule be employed also for further user information services, for example fax or data services. The user information therein requiring to be transmitted must in heterogeneous telephone networks be converted for each network section involved in a connection into a form of transmission corresponding to the respective type of trunk circuit employed by said network section, for example into analog or TDM signals or internet protocol data packets, and be switched in the network sections' switching equipment involved.